Advances in automation broaden punching capabilities(2)

When Is Automation Suitable?

• Standard Product. A standard product in large volumes with a common material type, thickness, and size remains the most obvious application. A consistent range of material types, sizes, and thicknesses means that part changeover is minimal, involving only a change in part program and slight changes to punch press tooling.
• Large, Heavy Workpieces. Automated load/unload devices can handle large or heavy workpieces that cannot be managed easily in a manual operation or when a two-operator setup is needed. Today’s punch presses feature larger tables than in the past and can accommodate nominal workpiece sizes up to 60 in. by 120 in. (1,500 mm by 3,000 mm).
• Material Utilization Maximization. Because automated systems accept large blank sizes, material can be better utilized to punch large workpieces. For example, a fabricator punching a 4-ft.-square blank could use an automated load/unload system to increase the blank size to 48 in. by 96 in. or 60 in. by 120 in. to nest more parts per blank. This is likely to improve productivity because more parts can be produced per workpiece, and material handling can be reduced.
• Labor Shortage. Freeing up machine operators from dedicated supervision of the equipment helps to address a skilled labor shortage or when labor is at a premium. Automating the material handling process provides an opportunity for operators to add value to other operations or expand their capabilities.
• Continuous, Uninterrupted Production. A material handling system combined with a high-speed punching machine allows a continuous, even work flow and a consistent level of productivity. Generally, load/unload systems complete a load cycle time in less than 25 seconds. While the punch press is punching, material can be replenished automatically for the next production run. Sheet handling time can be reduced as much as 80 percent.
• Lights-out Manufacturing. Automating punch press operations makes lights-out production feasible. Loading devices generally have material stack capacities of up to 10 in. (254 mm) and 10,000 pounds (4,545 kg), enhancing overall machine efficiency by providing high throughput volume without operator intervention. Marrying an automatic warehouse tower or multiple towers to a punch press with a large turret and tool capacity (for example, with up to 48 stations) further increases the autonomy of a system (see Figure 3). In addition, today’s automated systems can be equipped with a paging system to alert personnel when the machine has faulted or stopped. Webcam technology allows shops to monitor lights-out operations via the Internet.
• Safety Improvements. Automating punching also improves worker safety.

  Figure 3
  Linking the punch press with a robot to material storage units adds flexibility, optimizes material flow, and permits unattended operation.

  When Is Automation Not Suitable?

• High Frequency of Changeovers. Regular changeovers of material type, size, and thickness without a fully automatic system with material warehousing and tower likely require too much setup time.
• Part Quality Improvement. Although automation does allow more consistent gauging of the punch press, and therefore reduces opportunity for operator error, it does not significantly improve part quality.

What Do I Need to Know to Implement Automation?

Automation generally requires extensive training. Operators new to automation often underestimate the amount of training that is required. Be prepared to reserve the time to learn the system. Implementation often is a trial-and-error process because it varies with the application and because variables such as material mechanics (workpiece size, material type) influence material handling equipment setup.

For example, operators need to learn where machine work clamps should be positioned for consistent material gauging; how loader vacuum cups should be placed to load material accurately; and how to set the location of the unload clamp to effectively offload workpieces, whether they are shake-a-parts or full blanks.

Set reasonable expectations. The higher the level of automation, the more the user often expects from the system. Automation systems do not offer endless flexibility, however. For instance, a robotic material handling system is limited in the amount of weight the robot can lift and the distance it can reach for picking up blanks or stacking parts.

Allow adequate time for implementation. Anticipate up to a six-month implementation period for initial sales discussions, system configuration, installation, training, and support for a fully automated system (load/unload device with feed system or warehouse, robotic material handling system, and production cell). Automating with a simple load/unload device is a less time-consuming process and takes from one to two months.

Last, keep the level of automation in proportion with the value (and capabilities) of the punch press.